Electronic device comprising optical electronic components and fabricating process

ABSTRACT

An electronic device includes a first electronic component and a second electronic. Each electronic component includes a carrier substrate having a back side and a front side, an electronic chip including an integrated optical element, an overmolded transparent block encapsulating the electronic chip above the carrier substrate, and electrical connections between the electronic chip and electrical contacts of the carrier substrate. An overmolded grid encapsulates and holds the first and second electronic components. The grid is configured so that sides of the first and second electronic components are at least partially exposed.

PRIORITY CLAIM

This application claims the priority benefit of French Application forPatent No. 1909670, filed on Sep. 3, 2019, the content of which ishereby incorporated by reference in its entirety to the maximum extentallowable by law.

TECHNICAL FIELD

The present invention relates to the field of microelectronics and, moreparticularly, to the field of electronic devices comprising electronicchips including integrated optical elements for emitting and/orreceiving light.

BACKGROUND

Known electronic devices comprise a carrier substrate including anetwork of electrical connections, an electronic chip for emitting lightand an electronic chip for receiving light, said chips being mounted, adistance apart, above one side of the carrier substrate, and anencapsulating cover mounted on said side of the carrier substrate anddelineating chambers in which the electronic chips are respectivelylocated, this encapsulating cover containing apertures facing theoptical elements of the electronic chips, in which filters of the lightare generally provided.

Such electronic devices require a high number of fabricating andmounting operations.

SUMMARY

According to one embodiment, an electronic device is proposed, saidelectronic device comprising: at least one first and one secondelectronic component respectively comprising an opaque carrier substratehaving a back side and a front side, an electronic chip a back side ofwhich is mounted on the front side of the carrier substrate andincluding an integrated optical element facing a front side of thischip, an overmolded transparent block encapsulating the chip above thefront side of the carrier substrate, and electrical connections betweenthe chip and the back electrical contacts of the back side of thecarrier substrate, and an opaque overmolded grid for encapsulating andholding the electronic components, the encapsulating and holding gridbeing configured so that the back sides of the electronic components areexposed and so that at least those zones of the front sides of theelectronic components that are in front of the optical elements areexposed.

Thus, the electronic device forms an independent unit in which the griditself holds and encapsulates the electronic components, and theelectrical contacts of the carrier substrates of the electroniccomponents, which are distant from each other, are available for outsideconnections.

The encapsulating and holding grid may have a back side that is locatedin the same plane as the back sides of the electronic components.

The encapsulating and holding grid may have a front side located in thesame plane as a front side of at least one of the electronic components.

The encapsulating and holding grid may have at least one rim above thefront side of at least one of the electronic components, this rimdelineating an aperture.

The encapsulating and holding grid may comprise a peripheral wall and anintermediate partition extending between the electronic components.

The encapsulating blocks may be provided with a filtering material thatfilters light.

The filtering material may comprise layers above the encapsulatingblocks.

The filtering material may comprise particles included in the materialof the encapsulating blocks.

The optical element of one of the electronic components may be a lightemitter and the optical element of the other of the electroniccomponents may be a light receiver.

An electronic assembly is also provided, said assembly comprising areceiving substrate that includes a network of electrical connectionsand an electronic device mounted above the receiving substrate.

The electronic device is in a position such that the back sides of theelectronic components are adjacent to the receiving substrate and suchthat the back electrical contacts are connected to the electricalcontacts of the network of electrical connections of the receivingsubstrate.

A process for fabricating an electronic device is also provided, saidprocess comprising the following steps: providing at least one first andone second electronic component respectively comprising a carriersubstrate having a back side and a front side, an electronic chip a backside of which is mounted on the front side of the carrier substrate andincluding an integrated optical element facing a front side, anovermolded transparent block encapsulating the chip above the front sideof the carrier substrate, and electrical connections between the chipand the back electrical contacts of the back side of the carriersubstrate; mounting, at distance from each other, the electroniccomponents above a side of a provisional carrier substrate, in positionssuch that the back sides, or conversely the front sides, of theelectronic components are adjacent to the provisional carrier substrate;placing the electronic components in a cavity of a mold, in positionssuch that the provisional carrier substrate is adjacent to one face ofthe cavity and such that the front sides of the electronic componentsare at least partially adjacent to another face of the cavity, at leastin the zones of the optical elements, or conversely such that the backsides of the electronic components are adjacent to another face of thecavity; injecting an opaque encapsulating material into the cavity so asto obtain an encapsulating and holding grid containing spaces in whichthe electronic components are located; and demolding the obtainedelectronic device.

The process may comprise the following step: singulating the obtainedelectronic device so that the encapsulating and holding grid has aperipheral wall and an intermediate wall extending between theelectronic components.

The singulation may be obtained by sawing.

BRIEF DESCRIPTION OF THE DRAWINGS

Electronic devices will now be described by way of nonlimiting examplesof embodiments, which examples are illustrated by the appended drawings,in which:

FIG. 1 shows in cross section two separate electronic components;

FIGS. 2-5 show steps of fabrication of the electronic components of FIG.1;

FIG. 6 shows a cross-section of an electronic device comprising theelectronic components of FIG. 1;

FIGS. 7-10 show steps of fabrication of the electronic device of FIG. 6;

FIG. 11 shows a cross-section of another electronic device comprisingthe electronic components of FIG. 1;

FIGS. 12-15 show steps of fabrication of the electronic device of FIG.11; and

FIG. 16 shows a cross section of an electronic assembly comprising theelectronic device of FIG. 6.

DETAILED DESCRIPTION

With reference to FIGS. 1-4, individual electronic components 1 and 2and batch processes for manufacturing these electronic components willfirstly be described.

As illustrated in FIG. 1, the individual electronic components 1 and 2comprise carrier substrates 3 and 4, made of an opaque material, whichhave back sides 5 and 6 and front sides 7 and 8 and comprise opticalelectronic integrated circuit (IC) chips 9 and 10 that are mounted abovethe front sides 7 and 8 of the carrier substrates 3 and 4. The carriersubstrates are made of a dielectric material.

To achieve this, the back sides 11 and 12 of the chips 9 and 10 arefastened above the front sides 7 and 8 of the carrier substrate 3 and 4by way of adhesive layers 13 and 14. The carrier substrates 3 and 4 aremade of an opaque material such as, for example, an opaque resin.

The chips 9 and 10 include integrated optical elements 15 and 16 thatare oriented on the side of their front sides 17 and 18.

The optical element 15 of the chip 9 is a light emitter and the opticalelement 16 of the chip 10 is a light receiver.

The individual electronic components 1 and 2 comprise electricalconnections 19 and 20 that connect the chips 9 and 10 to back electricalcontacts 19 a and 20 a of the back sides 5 and 6 of the carriersubstrates 3 and 4.

For example, the electrical connections 19 and 20 comprise electricalconnection vias that pass through the carrier substrates 3 and 4 andthat are connected to back electrical contacts of the chips 9 and 10 byway of electrically conductive adhesive layers 13 and 14, and by way ofelectrical wires that are connected to front bumps of the chips 9 and10.

The electronic components 1 and 2 comprise overmolded encapsulatingblocks 21 and 22, made of a material that is transparent such as, forexample, an epoxy, so as to let light pass, above the front sides 7 and8 of the carrier substrates 3 and 4, in which blocks the chips 9 and 10and the electrical connections 19 and 20 are embedded.

The encapsulating blocks 21 and 22 have front faces 23 and 24 that areparallel to the carrier substrates 3 and 4 and lateral faces 25 and 26that follow the perimeter of the carrier substrates 4. Thus, theelectronic components 1 and 2 are parallelepipedal in shape.

Optionally, the front faces 23 and 24 of the encapsulating blocks 21 and22 are covered with layers 27 and 28 made of a material that filterslight, infrared rays for example.

According to one variant embodiment, the material from which theencapsulating blocks 21 and 22 is made could include specific particlesplaying the role of a filter of light.

The back sides 5 and 6 of the carrier substrates 3 and 4 form the backsides of the electronic components 1 and 2. The front faces 23 and 24 ofthe encapsulations 21 and 22, which optionally include the filteringlayers 27 and 28, form the front sides of the electronic components 1and 2.

The electronic components 1 and 2 may be fabricated in the followingway.

As illustrated in FIG. 2, a batch carrier substrate 29 is provided, saidsubstrate having a back side 30 and a front side 31 and including, in anumber of sites, through vias or networks of electrical connections forthe aforementioned electrical connections 19 and 20. These sites areadvantageously adjacent and rectangular or square, and are arranged inrows and columns.

In these separate sites and at distance, chips 9 and 10 are mountedabove the front side 31 of the batch carrier substrate 29 by way ofelectrically conductive adhesive layers 13 and 14, and the electricalconnections 19 and 20 are made such as described above.

Next, as illustrated in FIG. 3, the batch carrier substrate 29, equippedwith the chips 9 and 10, is placed in a cavity 32 of a mold 33, in aposition such that the batch carrier substrate 29 is adjacent to a face34 of the cavity 32 and such that a face 35, opposite and parallel tothe face 34, is located at distance above the chips 9 and 10.

Next, as illustrated in FIG. 4, an encapsulating material is injectedinto the cavity 32 of the mold 33 so as to form, by overmolding, a batchencapsulating block 36.

After demolding, optionally as illustrated in FIG. 5, a batch filteringlayer 37, for example taking the form of a film, is produced above thefront face of the batch encapsulating block 36.

Afterwards, a complete dicing operation 38, for example a sawingoperation, is carried out along rows and columns, through the batchcarrier substrate 29 and the batch encapsulating block 36, at distancefrom the chips 9 and 10, so as to obtain singulated or individualelectronic components 1 and 2 such as described above.

According to one variant embodiment, chips 9 could be mounted on the onehand solely on one specific batch carrier substrate and, by performingthe above operations, singulated electronic components 1 obtained, andon the other hand chips 10 could be mounted solely on one specific batchcarrier substrate and, by performing the above operations, singulatedelectronic components 2 obtained.

As illustrated in FIG. 6, an electronic device 101 comprises anovermolded encapsulating and holding grid 102 that contains distantspaces 103 and 104 in which an electronic component 1 and an electroniccomponent 2, such as described above, are located so that the back sides5 and 6 of the electronic components 1 and 2 lie in the same back plane.

Since the electronic components 1 and 2 have the same thickness, thefront sides 23 and 24 lie in the same front plane.

The encapsulating and holding grid 102 is configured so that the backsides 5 and 6 and the front sides 23 and 24 of the electronic components1 and 2 are exposed.

The encapsulating and holding grid 102 has a back side 105 that lies inthe same plane as the back sides 5 and 6 of the electronic components 1and 2 and has a front side 106 that lies in the same plane as the frontsides 23 and 24 of the electronic components 1 and 2.

The encapsulating and holding grid 102 envelops the periphery of theelectronic components 1 and 2 and thus has a peripheral wall 107 and anintermediate partition 108 that extends between the electroniccomponents 1 and 2.

The encapsulating and holding grid 102 is made of an opaque material.Thus, light cannot pass directly from one of the spaces 103 and 104 tothe other. More particularly, the light emitted by the emittingelectronic component 1 cannot directly reach the receiving electroniccomponent 2.

The electronic device 101 may be fabricated in the following way.

As illustrated in FIG. 7, having provided a provisional batch carrier109 taking the form of a sheet or of a film, electronic components 1 and2 are mounted, at distance from each other, on one side 110 of thisprovisional carrier 109, by placing the front sides 23 and 24 of theelectronic components 1 and 2 above the provisional carrier 109.

In a batch manufacturing fabricating process, pairs of electroniccomponents 1 and 2 are respectively mounted in sites of the provisionalbatch carrier 109, by way of an adhesive holding film. These sites areadvantageously adjacent and rectangular or square, and are arranged inrows and columns.

Next, as illustrated in FIG. 8, the electronic components 1 and 2,mounted on the provisional batch carrier 109, are placed in a cavity 111of a mold 112, in a position such that the provisional batch carrier 109bears against a face 113 of the cavity 111 and such that the back sides5 and 6 of the electronic components 1 and 2 bear against a face 114 ofthe cavity 111 opposite and parallel to the face 113.

According to one variant embodiment, the provisional batch carrier 109may also be used by way of wall of the cavity of the mold.

Next, as illustrated in FIG. 9, an opaque encapsulating material isinjected into the space left free in the cavity 111 so as to produce, byovermolding, a batch grid 115 for encapsulating and holding theelectronic components 1 and 2.

A cushioning film may be added in the cavity 111 against the face 114 inorder to prevent mold flash and to facilitate demolding.

After demolding, as illustrated in FIG. 10, the provisional batch holder109 is removed and a complete dicing operation 116 is carried out, forexample by sawing, along the rows and columns separating theaforementioned sites, through the batch grid 115, and at distance fromthe distant spaces 103 and 104, so as to obtain one or more singulatedelectronic devices 101.

According to one variant embodiment (shown equivalently in FIG. 12), theelectronic components 1 and 2 may be mounted upside down above the batchcarrier substrate 109, the back sides 5 and 6 being on the side of theprovisional batch carrier 109.

In this case, it is the front sides 23 and 24 that bear against a faceof the cavity 111 of the mold 112.

FIG. 11 illustrates an electronic device 201 that comprises anovermolded encapsulating and holding grid 202 that delineates distantspaces 203 and 204 in which an electronic component 1 and an electroniccomponent 2, such as described above, are located so that the back sides5 and 6 of the electronic components 1 and 2 lie in the same back plane.

The encapsulating and holding grid 202 is configured so that the backsides 5 and 6 of the electronic components 1 and 2 are exposed and sothat the front sides 23 and 24 of the electronic components 1 and 2 arepartially exposed.

The encapsulating and holding grid 202 has a back side 205 that lies inthe same plane as the back sides 5 and 6 of the electronic components 1and 2.

The encapsulating and holding grid 202 differs from the encapsulatingand holding grid 102 described above in that it is thicker than theelectronic components 1 and 2 and in that it comprises, apart from aperipheral wall 207 and an intermediate partition 208 between theelectronic components 1 and 2, a front wall 209 that extends above thefront sides 23 and 24 of the electronic components 1 and 2.

The front wall 209 contains apertures 210 and 211 that are located infront of the optical elements 15 and 16 of the chips 9 and 10, so as tolet light pass.

Thus, the encapsulating and holding grid 202 has, around the apertures210 and 211, front rims above the electronic components 1 and 2.

The electronic device 201 may be fabricated in the following way.

As illustrated in FIG. 12, having provided a provisional batch carrier109, taking the form of a sheet or a film, electronic components 1 and 2are mounted, at distance from each other, on a side 215 of thisprovisional carrier 214, by placing the back sides 5 and 6 of theelectronic components 1 and 2 above the provisional carrier 109.

In a batch fabricating process, pairs of electronic components 1 and 2are respectively mounted in sites of the provisional batch carrier 213.These sites are advantageously adjacent and rectangular and are arrangedin rows and columns.

Next, as illustrated in FIG. 13, the electronic components 1 and 2,mounted on the provisional batch carrier 214, are placed in a cavity 216of a mold 217, in a position such that the provisional batch carrier 214is adjacent to a face 218 of the cavity 216 and such that the frontsides 23 and 24 of the electronic components 1 and 2 are at distancefrom a face 219 of the cavity 216 opposite and parallel to the face 218.

The face 219 is provided with protruding embossments 220 and 221 thathave faces 222 and 223 that bear against the front sides 23 and 24 ofthe electronic components 1 and 2.

Next, as illustrated in FIG. 14, an opaque encapsulating material isinjected into the space left free in the cavity 216 so as to produce, byovermolding, a batch grid 224 for encapsulating and holding theelectronic components 1 and 2.

After demolding, as illustrated in FIG. 15, a complete dicing operation225 is carried out, for example by sawing, along the rows and columnsseparating the aforementioned sites, through the branches of the batchgrid 224, at distance from the distant spaces 203 and 204 in which theelectronic components 1 and 2 are located.

This dicing operation may be carried out directly on the provisionalbatch carrier 214 or on another carrier after the provisional batchcarrier 214 has been removed.

One or more singulated electronic devices 201 are then obtained, in theaforementioned locations.

According to one variant embodiment, in so far as one of the electroniccomponents 1 and 2 is thicker than the other, the holding andencapsulating grid could have a front side located in the same plane asthe front side of the thickest electronic component and, therefore, afront wall above the front side of the thinnest electronic component,this front wall containing an aperture.

FIG. 16 illustrates an electronic assembly 301 that comprises areceiving substrate 302 that includes a network of electricalconnections 303, for example an printed or integrated circuit board, andthat comprises the electronic device 101 described above with referenceto FIG. 6, said device being mounted on this receiving substrate 302.

The electronic device 101 is placed so that the back sides 5 and 6 ofthe electronic components 1 and 2 and the back side 105 of the holdingand encapsulating grid 102 are located facing a front side 304 of thereceiving substrate 302 and so that the back electrical contacts 19 aand 20 a of the electronic components 1 and 2 are connected to frontbumps 305 and 306 of the electrical connection network 303.

The electronic assembly 301 comprises electronic components (not shown)able to exchange electrical signals with the electronic components 1 and2 by way of the network of electrical connections 303.

In the electronic assembly 301, the electronic device 101 may bereplaced by the electronic device 201.

The invention claimed is:
 1. An electronic device, comprising: a firstelectronic component comprising a first opaque carrier substrate havinga first back side and a first front side, a first electronic chip havinga back side mounted to the first front side of the first opaque carriersubstrate, said first electronic chip including a first integratedoptical element at a front side of the first electronic chip, a firstovermolded transparent block encapsulating the first electronic chipabove the first front side of the first opaque carrier substrate, andfirst electrical connections between the first electronic chip and firstback electrical contacts at the first back side of the first opaquecarrier substrate; a second electronic component comprising a secondopaque carrier substrate having a second back side and a second frontside, a second electronic chip having a back side mounted to the secondfront side of the second opaque carrier substrate, said secondelectronic chip including a second integrated optical element at a frontside of the second electronic chip, a second overmolded transparentblock encapsulating the second electronic chip above the second frontside of the second opaque carrier substrate, and second electricalconnections between the second electronic chip and second backelectrical contacts at the second back side of the second opaque carriersubstrate; and an opaque overmolded grid for encapsulating and holdingboth the first and second electronic components, wherein the opaqueovermolded grid is configured so that respective back sides of the firstand second electronic components are exposed and so that at least zonesof respective front sides of the first and second electronic componentslocated in front of the first and second integrated optical elements areexposed.
 2. The device according to claim 1, wherein the opaqueovermolded grid has a back side that is located in a same plane as thefirst and second back sides of the first and second opaque carriersubstrates, respectively.
 3. The device according to claim 1, whereinthe opaque overmolded grid has a front side located in a same plane asthe front side of at least one of the first and second electroniccomponents.
 4. The device according to claim 1, wherein the opaqueovermolded grid has at least one rim above the front side of at leastone of the first and second electronic components, wherein said at leastone rim delineates an aperture extending through a front wall of theopaque overmolded grid to expose said zone.
 5. The device according toclaim 1, wherein the opaque overmolded grid comprises: a peripheral wallwhich surrounds the first and second electronic components and anintermediate partition extending between the first and second electroniccomponents.
 6. The device according to claim 1, wherein the first andsecond encapsulating blocks are provided with a filtering material thatfilters light.
 7. The device according to claim 6, wherein the filteringmaterial comprises a filter layer extending above each of the first andsecond encapsulating blocks.
 8. The device according to claim 6, whereinthe filtering material comprises particles included in an encapsulatingmaterial which forms the first and second encapsulating blocks.
 9. Thedevice according to claim 1, wherein the first integrated opticalelement is a light emitter and the second integrated optical element isa light receiver.
 10. An electronic assembly, comprising: a receivingsubstrate including a network of electrical connections; and anelectronic device, comprising: a first electronic component comprising afirst opaque carrier substrate having a first back side and a firstfront side, a first electronic chip having a back side mounted to thefirst front side of the first opaque carrier substrate, said firstelectronic chip including a first integrated optical element at a frontside of the first electronic chip, a first overmolded transparent blockencapsulating the first electronic chip above the first front side ofthe first opaque carrier substrate, and first electrical connectionsbetween the first electronic chip and first back electrical contacts atthe first back side of the first opaque carrier substrate; a secondelectronic component comprising a second opaque carrier substrate havinga second back side and a second front side, a second electronic chiphaving a back side mounted to the second front side of the second opaquecarrier substrate, said second electronic chip including a secondintegrated optical element at a front side of the second electronicchip, a second overmolded transparent block encapsulating the secondelectronic chip above the second front side of the second opaque carriersubstrate, and second electrical connections between the secondelectronic chip and second back electrical contacts at the second backside of the second opaque carrier substrate; and an opaque overmoldedgrid for encapsulating and holding both the first and second electroniccomponents, wherein the opaque overmolded grid is configured so thatrespective back sides of the first and second electronic components areexposed and so that at least zones of respective front sides of thefirst and second electronic components located in front of the first andsecond integrated optical elements are exposed; wherein said electronicdevice is mounted to the receiving substrate in a position such that therespective back sides of the first and second electronic components areadjacent to the receiving substrate; and wherein the first and secondback electrical contacts are connected to the electrical contacts of thenetwork of electrical connections of the receiving substrate.
 11. Theassembly according to claim 10, wherein the opaque overmolded grid has aback side that is located in a same plane as the respective back sidesof the first and second electronic components.
 12. The assemblyaccording to claim 10, wherein the opaque overmolded grid has a frontside located in a same plane as the front side of at least one of thefirst and second electronic components.
 13. The assembly according toclaim 10, wherein the opaque overmolded grid has at least one rim abovethe front side of at least one of the first and second electroniccomponents, wherein said at least one rim delineates an apertureextending through a front wall of the opaque overmolded grid to exposesaid zone.
 14. The assembly according to claim 10, wherein the opaqueovermolded grid comprises: a peripheral wall which surrounds the firstand second electronic components and an intermediate partition extendingbetween the first and second electronic components.
 15. The assemblyaccording to claim 10, wherein the first and second encapsulating blocksare provided with a filtering material that filters light.
 16. Theassembly according to claim 15, wherein the filtering material comprisesa filter layer extending above each of the first and secondencapsulating blocks.
 17. The assembly according to claim 15, whereinthe filtering material comprises particles included in an encapsulatingmaterial which forms the first and second encapsulating blocks.
 18. Theassembly according to claim 10, wherein the first integrated opticalelement is a light emitter and the second integrated optical element isa light receiver.